Sewer systems are a potentially major source of urban groundwater pollution; water can leak through structural faults (or ‘exfiltration’ — i.e. through fractures or intruding tree roots) and be absorbed by surrounding soil, which can introduce nutrients, suspended solids and microbes into nearby water bodies. Estimating sewer leakage and exfiltration is important for effective management of urban waste-water systems, say the researchers of a new study that explores sewer leakage at the national scale in Germany. Click here to read more